"""
69. Sqrt(x)

Implement int sqrt(int x).

Compute and return the square root of x, where x is guaranteed to be a non-negative integer.

Since the return type is an integer, the decimal digits are truncated and only the integer part of the result is returned.

Example 1:

Input: 4
Output: 2

Example 2:

Input: 8
Output: 2
Explanation: The square root of 8 is 2.82842..., and since the decimal part is truncated, 2 is returned.
"""


def mySqrt(x):
    if x == 0:
        return 0

    left = 1
    right = x
    while True:
        mid = left + (right - left) // 2
        if mid > x / mid:
            right = mid - 1
        else:
            if mid + 1 > x / (mid + 1):
                return mid
            else:
                left = mid + 1
